It is necessary in the bottling and packaging of fluids, particularly those fluids used in medicine and dentistry, that the pipe runs of the packaging machine as well as the devices used to form the container and to inject a dose of fluid into the container, are kept free of microorganisms and other contaminants. To this end a sterilizing agent such as a vapor having transferable latent heat, e.g., steam, is utilized.
The machines used for expeditious liquid packaging are devices which mold, fill and seal liquid containers in one operation. Such machines are shown in U.S. Pat. No. Re. 27,155 to Hansen and usually comprise: an extrusion head for extruding thermoplastic tubing; at least one sectional mold assembly which is arranged to enclose a length of the extruded tubing; and a nozzle assembly arranged to be introduced into the upper end of the length of tubing within the mold assembly for supplying a fluid under pressure to expand the tubing into contact with the mold and thereby form the body of the container and for filling the formed container. In addition, a metering device having inlet and outlet valves and a displacement piston is provided in conjunction with the nozzle assembly.
U.S. Pat. No. 3,650,678 to Hansen shows a typical sterilization system. Ordinary stop cocks and three-way valves are employed and the flow paths selected or utilized which are not completely touched by the sterilizing medium. Moreover, relatively complicated cam-actuated valves are used to deliver the product or filler material to and from the dosing chamber of the dosing device. These valves, while easy to clean, require the metering device to be cycled which requirement unnecessarily complicates the procedure. Most importantly, no provision is made for "on-line testing" of the bacteriological filters. Due to the nature of the sterilizing system, the sterilizing medium is often wasted and not ducted to every part of the machine which could become a potential source of contamination. Live steam can be discharged directly to the atmosphere where it is a potential personnel hazard. Finally, although some lines are sterilized prior to use, the air subsequently passing through these lines is not always filtered. The net result of these various shortcomings is that the packaging machine is not always used to its fullest advantage.
An improved apparatus or system for sterilizing the critical components of a machine used in liquid packaging applications, especially for pharmaceuticals, would be desirable and would go far to improve the utilization of those machines and to insure that the product packaged has the highest purity.